When manufacturing a metallic sheet continuously, predetermined processes are made on a long metallic sheet while it is travelling. In this travelling passage, a plurality of guide rolls are generally disposed together with a suitable number of displacement correcting rolls for correcting the displacement of a metallic sheet due to its sidemovement. As a displacement correcting roll of this type, there is conventionally known, for example, a roll R schematically shown in FIG. 7 (I) to (III). The roll R is rotatably supported by a shaft and is swingable with one end of the rotary shaft serving as a fulcrum. If a metallic sheet S which windingly travels on the roll R exhibits sidemovement and is displaced to the position shown by chain lines in FIG. 7 (I), the roll R is adapted to swing at its free end in a predetermined direction to restore the sheet S to a correct position to prevent the sheet S from coming off from the roll R.
As discussed hereinbefore, the displacement of the metallic sheet S is corrected by swingingly inclining the roll R. However, the inclination of the roll R exerts tension to the sheet S at its displaced side. Such tension causes the sheet S at its displaced side to be stretched, thereby to disadvantageously lower the quality of the metallic sheet.
Further, in order to swing the roll R, a sufficient space and a peculiar swing device are required. The entire displacement correcting apparatus therefore becomes large-sized, costing a great deal. Moreover, such roll R is slow in correcting action and lacks a speedy reaction.